FR2819420A1 - Use of activated carbon fiber material to make devices for protection against effects of biological agents, especially biological warfare agents - Google Patents

Abstract

An activated carbon fiber material (texture) is used to make devices for protection against the effects of biological agents. The material is produced by impregnating a cellulosic fiber material with an inorganic dehydrating agent, heating the material to 350-500 deg C at a rate of 1-15 deg C/minute, maintaining this temperature to carbonize the fibers, and washing the material to obtain a product with a surface area of at lest 600 m<2>/g. An Independent claim is also included for a product for protection against the effects of biological agents, comprising an activated carbon fiber material as above containing an additive against the effects of biological agents, the additive being fixed during heat treatment of the material.

Description

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The present invention relates to protection against the effects of biological agents, in particular that of human beings, in particular in the context of protection against nuclear-biological-chemical weapons. To this end, it relates to a new application of a known material, and to a new product for protection against the effects of biological agents.

In this specification, the term "bacteriostatic" applies to materials which stop the proliferation of bacteria. The term "bactericidal" applies to materials capable of destroying at least some bacteria.

The term "antibacterial" applies to both bacteriostatic and bactericidal materials. The expression "NBC garment" denotes a garment for protection against the effects of nuclear-biological-chemical weapons.

The invention is described in its application to NBC garments, although it has much broader applications, in particular to products other than garments and underwear, such as tents and protective curtains, and to fields where protection against the effects of biological agents is important, in particular in the medical and civil protection fields.

Before describing the problem solved by the invention, it is appropriate to consider what are the main current types of protective clothing against the effects of nuclear-biological-chemical weapons.

A first, relatively old type of NBC garment is waterproof, based on isobutyl rubber. Protection against the effects of biological agents is obtained thanks to the seal which prevents the passage of infecting and intoxicating agents. The disadvantage of this type of garment is that it prevents the passage of air and water vapor, and therefore can only be worn for short periods.

A second, more recent type of NBC garment allows breathing, because it is based on the principle of filtration. A particularly useful example of a garment is formed from a polyurethane foam having an activated carbon filler. In this type of clothing, protection against the effects of biological agents is provided by the use of adjuvants added to the polyurethane foam. In protective clothing of this second type, the activated carbon is most often a divided charge of activated carbon providing protection against chemical agents.

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Clothing of this second type, however, has the drawback of not being washable, because washing them considerably reduces their activity against biological and chemical agents, and of gradually losing their protective properties. It is therefore difficult to produce clothing of this second type having both sufficient activities against very diverse biological weapons, and sufficient persistence of these activities over time.

It is already known to give antibacterial properties to textures of activated carbon, obtained from viscose or pitch and having by themselves no specific effect against biological agents, by various treatments with adjuvants, such as salts of. silver and copper, as described for example in the articles “Antibacterial pitch-based activated carbon fiber supporting silver” by Ch. Y. Li et al., Carbon, Vol. 36, nu 1-2, p. 61-65, and "Preparation and characterization of antibacterial viscose-based activated carbon fiber supporting silver" by Y. L. Wang et al., Carbon, Vol. 36, no 11, p. 1567-1571.

Given the diversity and specific activity of biological weapons (infecting agents such as fungi, bacteria, rickettsiae and viruses, or intoxinating agents such as protein toxins, peptides and low molecular weight toxins), it is desirable to have available 'a material which on the one hand gives the advantages of clothing allowing breathing, and on the other hand has good protective properties against the effects of biological agents, even after washing.

Tests have been carried out within the framework of the invention for the determination of treatments to be applied to various support materials so that they have sufficient activity against biological weapons and sufficient persistence of this activity.

During these tests, it was then unexpectedly realized that a commercially available support material for industrial filtration applications possessed certain bactericidal properties and could thus be advantageously used for NBC garments, without any treatment. additional specific. It was then realized that it was possible to modify and strengthen these bactericidal properties by action during the very process of manufacturing this material.

The process for manufacturing this material is described in document FR-A-2 760 759. This indicates that a fiber texture of a material

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350 et 500 C et par maintien à cette température,. Le produit obtenu est une texture activée en fibres de carbone. La seule application envisagée dans ce document est la filtration des fluides, pour le traitement des effluents gazeux ou liquides. On sait de façon générale que le carbone activé possède normalement des propriétés bactériostatiques, mais pas d'activité bactéricide. cellulosic precursor of carbon, such as yarns, cables, fabrics, layers of yarns or cables, felts, mats and knits, can be impregnated with a composition containing phosphoric acid, chloride of zinc, potassium sulfate, potassium hydroxide, diammonium phosphate or ammonium chloride, then heat treated by rising at a rate of 1 to 15 C / min to a temperature between

350 and 500 C and by maintaining at this temperature ,. The product obtained is an activated carbon fiber texture. The only application envisaged in this document is the filtration of fluids, for the treatment of gaseous or liquid effluents. It is generally known that activated carbon normally has bacteriostatic properties, but no bactericidal activity.

The invention relates to the use of the teachings of these surprising results of the aforementioned tests, in the application of the product obtained by the process of document FR-A-2 760 759 and of similar products for protection against the effects of biological agents.

des propriétés bactéricides de ce matériau. More precisely, the invention relates on the one hand to the new application of this known material for protection against the effects of biological agents, and on the other hand to new products obtained by reinforcement or modification.

bactericidal properties of this material.

de réagir avec le matériau précurseur de carbone pour assurer une déshydratation, puis le traitement thermique de la texture imprégnée à une température suffisante pour provoquer la transformation du matériau précurseur en carbone pratiquement par montée à une vitesse de 1 à 15 C/min jusqu'à une

température comprise entre 350 et 500 C et maintien à cette température, puis le lavage de la texture qui donne une texture activée en fibres de carbone ayant une surface spécifique d'au moins 600 m2/g. In a first aspect, the invention relates to the application to the manufacture of devices for protection against the effects of biological agents, of an activated carbon fiber texture, obtained by a process which comprises the impregnation of a carbon fiber texture. fibers of a cellulosic material precursor of carbon by a composition containing at least one mineral constituent capable of

to react with the carbon precursor material to ensure dehydration, then the heat treatment of the impregnated texture at a temperature sufficient to cause the transformation of the precursor material into carbon practically by rising at a rate of 1 to 15 C / min up to a

temperature between 350 and 500 ° C. and maintaining at this temperature, then washing the texture which gives an activated carbon fiber texture having a specific surface area of at least 600 m 2 / g.

In a preferred embodiment, during the manufacture of the activated texture, the impregnation of the texture with a composition containing at least one mineral component is carried out with a component having a dehydration effect and / or affecting the heat treatment. . This composition can

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ainsi contenir des sels choisis parmi les sels d'argent, les sels d'ammonium quaternaire, les sels de cuivre, les composés organophosphorés et leurs mélanges.

thus contain salts chosen from silver salts, quaternary ammonium salts, copper salts, organophosphorus compounds and mixtures thereof.

In another embodiment, after the manufacture of the activated texture, that is to say after the heat treatment step, the activated carbon fiber texture undergoes treatment with an active adjuvant against the effects of the agents. biological.

Preferably, the activated carbon fiber texture is combined with another textile material, in the form of a complex fabric.

la transformation du matériau précurseur en carbone pratiquement par montée à une vitesse de 1 à 15 C/min jusqu'à une température comprise entre 350 et 500 C et maintien à cette température, puis le lavage de la texture, et contenant un adjuvant actif contre les effets des agents biologiques, incorporé à la texture, l'adjuvant actif contre les effets des agents biologiques étant à un état fixé

obtenu au cours du traitement thermique de la texture. The invention also relates to a new product for protection against the effects of biological agents, consisting of an activated carbon fiber texture, obtained by a process which comprises the impregnation of a fiber texture with a carbon precursor cellulosic material. by a composition containing at least one mineral constituent capable of reacting with the carbon precursor material to ensure dehydration, then the heat treatment of the impregnated texture at a temperature sufficient to cause

the transformation of the precursor material into carbon practically by rising at a rate of 1 to 15 C / min to a temperature between 350 and 500 C and maintaining at this temperature, then washing the texture, and containing an active adjuvant against the effects of biological agents, incorporated into the texture, the adjuvant active against the effects of biological agents being in a fixed state

obtained during the heat treatment of the texture.

Preferably, the adjuvant active against the effects of biological agents is chosen from the group which comprises silver salts, quaternary ammonium salts, copper salts, organophosphorus compounds and mixtures thereof.

In one embodiment, the adjuvant active against the effects of biological agents is in a fixed state obtained by subsequent treatment of the activated carbon fiber texture. In a variant, the product contains another adjuvant active against the effects of biological agents, incorporated by attachment to the texture obtained by the heat treatment, the activated carbon fiber texture having a specific surface area of at least 600 m2 / g.

The concentration of the adjuvant is advantageously selected so that the bactericidal activity of the product for protection against the effects of an agent

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biologique particulier, représentée par le logarithme du nombre d'unités formant colonie, soit au moins égale à 5.

particular biological, represented by the logarithm of the number of colony-forming units, i.e. at least equal to 5.

In a very advantageous embodiment, the product is in the form of a complex fabric comprising the activated carbon fiber texture and a textile material having bacteriostatic properties.

When the product in the form of a complex fabric is used as a garment or undergarment, the textile material having bacteriostatic properties is disposed on the inner side of the garment or undergarment, intended to be in contact with the skin.

In another very advantageous embodiment, the product is in the form of a complex assembly comprising the activated carbon fiber texture and a film impervious to the active principles of biological weapons.

The essential features of the invention will now be considered in more detail.

Unlike conventional granular activated carbons, the activated carbon fiber texture does not undergo significant performance degradation in the presence of water vapor. This property is demonstrated by determining the breakthrough time of acetone in dry and humid environments (80% relative humidity).

The activated carbon fiber texture comprises carbon filaments having a diameter of the order of 20 µm and having a microporosity, that is to say having pores with a dimension of the order of a few nanometers (about 2 nm or less). These filaments do not absorb water in the liquid or condensed state, in particular that which forms by capillary condensation. The texture can therefore be used in atmospheres with 50-60% relative humidity, and more, especially in tropical climates. The BET specific surface area of the activated texture is generally of the order of approximately 1000 to 1200 m2 / g.

Tests are carried out in order to demonstrate that the bactericidal activity implemented according to the invention for protection against biological agents on the one hand is real, and on the other hand is not due to the use of a simple carbonaceous material, nor to the use of any fabric of carbon fibers, but indeed to the activated texture of carbon fibers obtained by the aforementioned process.

In the tables which follow, the bactericidal activity is given in the form of the logarithm of the number of colony-forming units determined on

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colonies de Staphylococcus Aureus cultivées sur gélose, à des concentrations comprises entre 2, 8. 104 et 1, 26. 105 unités.

colonies of Staphylococcus Aureus cultured on agar, at concentrations of between 2.14 and 1.26.105 units.

If this logarithm is between -2 and +2, the sample is considered to be bacteriostatic; if it is less than -2, the sample is considered to have bactericidal activity.

Test 1: effective existence of a bactericidal activity Activated carbon fiber texture: side with 1 x 1 thread from the Messier-Bugatti company, produced according to document FR-A-2 760 759 Comparative sample: 100% cotton (mesh)
In a first test, the bactericidal activity of the activated carbon fiber texture was determined. The results are shown in Table 1.

Table 1

<tb>
<tb> Sample <SEP> Activity <SEP> 0 <SEP> h <SEP> Activity <SEP> 24 <SEP> h <SEP> Difference
<tb> Cotton <SEP> 100 <SEP>% <SEP> 4, <SEP> 8 <SEP> 7, <SEP> 6 <SEP> 2, <SEP> 8
<tb> Texture <SEP> activated <SEP> 4.45 <SEP> 0-4.45
<tb>

While it appears that the cotton causes proliferation of the colonies, the fabric used according to the invention causes total destruction of the colonies.

Test 2: comparison with a carbonaceous material Activated carbon fiber texture: as in test 1 Comparative sample: carbonaceous foam
In the second test, the activated carbon fiber texture is compared to a carbonaceous foam.

Table 2

<tb>
<tb> Sample <SEP> Activity <SEP> 0 <SEP> h <SEP> Activity <SEP> 24 <SEP> h <SEP> Difference
<tb> Carbonaceous <SEP> foam <SEP> 4.45 <SEP> 3.6-0, <SEP> 85
<tb> Texture <SEP> activated <SEP> 4.45 <SEP> 0-4.45
<tb>

It is noted that the carbonaceous foam has a simple bacteriostatic activity.

It therefore appears that it is not the carbon itself which is the origin of the bactericidal effect employed according to the invention.

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Test 3: comparison with a carbon fabric Texture activated carbon fibers: as in test 1 Comparative sample:
Doped carbon tissue after activation with silver salts
In this third test, the activated texture of carbon fibers is compared to a carbon fabric impregnated with silver salts after activation. This comparative sample, available commercially, is an activated carbon jersey obtained by carbonization of a viscose precursor and activated with an oxidizing agent under a carbon dioxide atmosphere up to a final temperature of 900 C. The amount of salts d The silver deposited on the carbon fabric is between 0.15 and 0.3%. This product also contains traces of aluminum, silicon, zinc, sodium and sulfur.

Table 3

<tb>
<tb> Sample <SEP> Activity <SEP> 0 <SEP> h <SEP> Activity <SEP> 24 <SEP> h <SEP> Difference
<tb><SEP> carbon <SEP> fabric <SEP> 5,1 <SEP> 4,8-0, <SEP> 3
<tb> Texture <SEP> activated <SEP> 4.45 <SEP> 0-4.45
<tb>

It appears that the carbon tissue is simply bacteriostatic; it is therefore the activated carbon fiber texture used according to the invention which is the only source of the bactericidal effect.

In other tests, we tested the lamination of a cotton mesh having undergone a bacteriostatic treatment ("Sanitized").

Test 4: effect of laminating a sheet Activated carbon fiber texture, as in test 1, associated with a bacteriostatic "Rhovyl AS" mesh, tested on each of its two faces
In this test, we compare the bactericidal actions of the two faces of a complex fabric formed of an activated texture of carbon fibers, laminated to a mesh of chlorofiber.

Table 4

<tb>
<tb> Sample <SEP> Activity <SEP> 0 <SEP> h <SEP> Activity <SEP> 24 <SEP> h <SEP> Difference
<tb> Complex <SEP> fabric <SEP> 4,8 <SEP> 3,4-1, <SEP> 4
<tb> side <SEP> mesh
<tb> Complex <SEP> fabric <SEP> 4, <SEP> 45 <SEP> 0-4, <SEP> 45
<tb> side <SEP> texture <SEP> enabled
<tb>

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As for the mesh, the complex fabric only has a bacteriostatic effect, and it makes it possible to obtain good comfort in contact with the skin.

We will now consider examples of products according to the invention First example of product
A material suitable for making NBC clothing is produced, comprising an inner cotton mesh, giving good comfort, an activated carbon fiber texture, used according to the invention, and, on the outside, a polyamide mesh.

société de la société Messier-Bugatti sous la référence"F-TEX N1000". Il s'agit d'une texture à armure satin de 4 ayant une surface BET de 1 200 m2/g et une masse surfacique d'environ 120 g/m2. More precisely, the activated carbon fiber texture, produced according to the aforementioned patent FR-A-2 760 759, is of the type marketed by the

company of the Messier-Bugatti company under the reference "F-TEX N1000". It is a satin weave texture of 4 having a BET surface area of 1200 m2 / g and a basis weight of approximately 120 g / m2.

The aforementioned activated texture is laminated, on the face intended to be in contact with the skin, with a cotton jersey of 100 g / m2 having undergone a “Sanitized” treatment which gave it bacteriostatic properties. Laminating can be done by film or adhesive powder.

The other side of the activated texture "F-TEX N 1000" is laminated with a polyamide mesh of 30 g / m2.

Although cotton jersey has been cited as a web with bacteriostatic properties, it is possible to use other fibers with bacteriostatic properties, such as "Amicor" AB, AF and PLUS from Acordis, "Microsafe AM" from Hoechst , "Liverfresh A" and "Lufnen VA" from Kanebo, and 'Viscofresh "and" Modalfresh "from Lenzing. It is also possible to use conventional commercial textile materials bearing a finish (for example based on trichlosan or pyrethroid ).

Further, although the use of lamination has been cited for the association of the various webs of the complex fabric, the operation can be carried out by various other methods, for example by sewing or knitting. The method used is chosen so that the activated carbon fiber fabric cannot come into contact with the skin on the side carrying the inner mesh.

The complex fabric obtained has a total thickness of the order of 1 mm and a basis weight of approximately 250 g / m2. It constitutes a permeable textile support having antibacterial properties. It also has the following properties:

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good adsorption of toxic warfare agents, bacteriostatic activity, on the side intended to be in contact with the skin, bactericidal activity, on the side exposed to biological weapons, a property of non-flammability, good washability, good comfort, and mechanical resistance compatible with the use of clothing.

Applications of the product of the first example
1) The product obtained is used for the manufacture of socks, underwear and hoods providing protection against biological agents.

2) The product obtained is associated with a fabric having undergone a water and oil repellent treatment, and it is then used for making NBC protective clothing, by implementing the teachings of document FR-91 07 806, and gloves by implementation of the teachings of document FR-A-2 752 994.

Second product example
The product of the first example is used, and it is combined with a film according to the teachings of document FR-2 656 459, to obtain a waterproof textile support for biological protection. This material is used in the manufacture of articles for the protection of man (clothing, gloves, boots, diving suits) and his immediate environment (tents, bags, curtains, containers), in particular for medical applications and in theaters of 'operations.

Other embodiments
Various exemplary embodiments have been described in which the bactericidal effect is due almost solely to the activated carbon fiber texture obtained by the process of the aforementioned document FR-A-2 760 759. However, given the great diversity of biological weapons , it may be necessary to enhance the bactericidal activity specific to a particular biological weapon (infectious agents or intoxinants). This reinforcement can be carried out either by a conventional method of treating the texture activated by a specific adjuvant, or preferably by adding a specific adjuvant to the composition for impregnating the texture of the cellulose precursor before the heat treatment giving the texture. activated. In the latter case, the adjuvant

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specific is resistant to washing and therefore allows the making of all kinds of clothing and underwear, including socks.

Advantageous properties of the products according to the invention
The products according to the invention have the following properties.

They provide adsorption of toxic warfare agents, due to the activated carbon fiber texture. This adsorption is not very sensitive to washing.

They exhibit bacteriostatic activity on the skin side, given by the inner mesh, preferably made of cotton.

Their bactericidal activity is given by the activated carbon fiber texture, as indicated above. This activity can be enhanced by adapting the impregnation composition used either for the direct increase of the bactericidal effect, or for the creation of conditions allowing good fixation of specific bactericidal agents by subsequent treatment.

They have a non-flammability property which is also given by the activated carbon texture.

They have a good comfort which is given by the inner mesh which can be adapted to the particular application envisaged.

They have high mechanical strength largely due to the inner mesh which can be very sturdy. They thus resist the constraints of the making, in particular by sewing.

Garments made with a product according to the first example, operating according to the principle of breathing, can be worn for long periods. They can be washed several times, because neither the constituent elements nor the adjuvants separate in the washing.

The product in the form of a complex fabric is relatively thin and allows the preparation of garments and underwear of reduced thickness. The assembly produced has good thermal stability and is in particular non-flammable under the usual conditions of use.

At the end of their life, these clothes can be easily incinerated since they only emit non-toxic gases and have an extremely low ash content (less than 1%).

Of course, various modifications can be made by those skilled in the art to the products and to the application which have just been described by way of non-limiting example without departing from the scope of the invention.

Claims (10)

mineral constituent capable of reacting with the carbon precursor material to ensure dehydration, then the heat treatment of the impregnated texture at a temperature sufficient to cause the transformation of the precursor material into carbon practically by rising at a rate of 1 to 15 C / min up to a temperature between 350 and 500 ° C. and maintaining at this temperature, then washing the texture which gives an activated carbon fiber texture having a specific surface area of at least 600 m2 / g.

CLAIMS 1. Application to the manufacture of devices for protection against the effects of biological agents, of an activated carbon fiber texture, obtained by a process which comprises the impregnation of a fiber texture of a cellulosic material precursor of carbon by a composition containing at least one 2. Application according to claim 1, characterized in that, during the manufacture of the activated texture, the impregnation of the texture with a composition containing at least one mineral constituent is carried out using a composition containing salts chosen from silver salts, quaternary ammonium salts, copper salts, organophosphorus compounds and mixtures thereof. 3. Application according to claim 1, characterized in that, after the

production of the activated texture, that is to say after the heat treatment step, the activated carbon fiber texture undergoes treatment with an active adjuvant against the effects of biological agents. 4. Application according to any one of claims 1 to 3, characterized in that the activated carbon fiber texture is combined with another textile material, in the form of a complex fabric. 5. Product for protecting against the effects of biological agents, characterized in that it comprises an activated carbon fiber texture, obtained by a process which comprises the impregnation of a fiber texture with a carbon precursor cellulosic material. with a composition containing at least one mineral constituent capable of reacting with the precursor material of

carbon to ensure dehydration, then heat treatment of the impregnated texture at a temperature sufficient to cause the transformation of the precursor material into carbon practically by rising at a rate of 1 to 15 C / min up to a temperature between 350 and 500 C and holding at that temperature, then washing the texture, and containing <Desc / Clms Page number 12> an adjuvant active against the effects of biological agents, incorporated into the texture, the adjuvant active against the effects of biological agents being in a fixed state obtained during the heat treatment of the texture. 6. Product according to claim 5, characterized in that the adjuvant active against the effects of biological agents is chosen from the group which comprises

silver salts, quaternary ammonium salts, copper salts, organophosphorus compounds and mixtures thereof. 7. Product according to one of claims 5 and 6, characterized in that it contains another active adjuvant against the effects of biological agents, incorporated by attachment to the texture obtained by the heat treatment, the activated carbon fiber texture having a specific surface of at least 600 m2 / g. 8. Product according to one of claims 5 and 6, characterized in that an active adjuvant against the effects of biological agents is in a fixed state obtained by a subsequent treatment of the activated carbon fiber texture. 9. Product according to any one of claims 5 to 7, characterized in that it is in the form of a complex fabric comprising the activated carbon fiber texture and a textile material having bacteriostatic properties. 10. Product according to any one of claims 5 to 7, characterized in that it is in the form of a complex assembly comprising the activated carbon fiber texture and a sealed film preventing the passage of the active principles of biological weapons.